A trademark used for underwear. This trademark often occurs in lowercase in print: “The venerable white-underwear company . . . had dabbled in socks, sweats, and fashion skivvies” (Advertising Age). “About 500 yards away, on three destroyers snubbed up to the dock, men were clambering on the deck in their skivvies” (Smithsonian).

(noun)Any negative connotation having to do with emotions or actions of a girl on her period.

Boyfriend: Rachael keeps getting mad at everything I do... And everyone else she talks to. I try to love her with all my heart. What am I doing wrong?
His friend: Dude, maybe she's just skivvy right now.
Boyfriend: Oh, you're probably right. I can see how her skivviness can makethis way. Thanks, man. I'll just wait out the skiv